10. "Cordially,"What it means: Cordial comes from the Latin cordialis, and means "of or for the heart." Some etymology manuals suggest it means something closer to "sincere."Pros and cons: Strictly based on the definition, "cordially" would appear to possess personal undertones. And yet, it can also come off as stiff and formal, making it ideal for business correspondence and not much else. Assuming you're not an automaton, there are better options further down this list. Typically used by: Job-hunters sending "thank you for meeting with me" notes. Nigerian email scammers.

9. "Cheers,"What it means: By the late 14th century, the verb cheer had taken on two meanings: (1) To "cheer up, humor, [or] console," and (2) "to entertain with food or drink." Let's go with the latter.Pros and cons: It's friendly. Chummy, even. At the same time, signing emails this way makes it sound like you really need a drink. Esquire's Rule No. 351 states that "Americans who say 'cheers' are pretentious twits." Typically used by: The British. That co-worker who can't wait for Friday.

8. "Regards,"What it means: Short for "kindest regards," at least according to Emily Post's seminal work, Etiquette. "It is too bad that the English language does not permit the charming and careful closing of all letters in the French manner," writes Post (p.294). Ergo, "kindest" gets the snip.Pros and cons: This is one of those divisive sign-offs. On one hand, its formality gives you a professional blank slate — great for that new co-worker you can't quite get a read on yet. Others find it cold. According to one commenter at Giga Om, "regards" communicates something akin to "go to hell."Typically used by: Frenemies. Go-getters with slightly sociopathic tendencies.

7. "Take care,"What it means: Shorthand for "take care of yourself." Pros and cons: It's friendly, conversational, and versatile. (Everyone needs to take care of themselves!) But ideally, "take care" should be left for people you know in real life. Barbara Bogaev at Marketplace makes a good point: "Take care" might sound insincere to someone you don't really know very well. Typically used by: That co-worker you just completed a 20-week project with. Drake and Rihanna, I'm assuming.

6. "Warmly,"What it means: "With warmth," but in adverb form.Pros and cons: It's succinct and good natured. Think "regards" drained of its latent nastiness. Richard Kirshenbaum, chief executive of the ad firm Kirshenbaum Bond & Partners, once told The New York Times that "warmly" felt like a comfortable middle between "love" and "sincerely." "I want to convey a sense of warmth and passion, but also be appropriate," he said. Typically used by: Ad execs. Despondent millennials. Facebook "friends" asking for a favor.

5. "Xoxo," "xo," and all derivativesWhat it means: Hugs and kisses. (Defining X as "kiss" goes all the way back to 1763, according to The Oxford English Dictionary.)Pros and cons: Last year, The Atlantic investigated xo's quiet invasion of the workplace lexicon: "xo is not a habit unique to 20‑somethings reared on Gossip Girl," wrote The Atlantic's Jessica Bernett and Rachel Simmons. "It has surfaced in the digital correspondence of everyone from Arianna Huffington to Nora Ephron…. In Diane Sawyer’s newsroom, staffers say, the anchor uses xo so frequently that its omission can spark panic." Indeed, xo's colloquial brevity is feminizing the workplace — for better or worse. Typically used by: Arianna Huffington. Nora Ephron. Diane Sawyer.

4. "Best," What it means: Short for "best wishes." Pros and cons: "Best" can sometimes feel abrupt. If you're sensitive to other people's feelings, you can always tack on a "best regards" or the aforementioned "best wishes." But "best" fits a wide variety of individual case uses, from acquaintances to strangers to bosses. I'd argue that its open-endedness is part of its appeal. According to Lifehacker, "best" is friendly with natural undertones, and like most sign-offs on this list, is ideal for emails with people you're not too familiar with. Typically used by: Outside vendors. The tech support guy.

3. (None)What it means: ….Pros and cons: In this case, silence can speak volumes. Just bear in mind that you can trigger a variety of thought patterns, often simultaneously:• "I have no time for nonsense."• "I don't want to waste your time with nonsense."• "I'm too indecisive to think about a proper sign-off."• "I am possibly a mean person."• "You're on thin ice at the moment."Typically used by: Your boss when you request extra vacation time. Frank Sinatra, apparently.

2. "Thanks," "Thank you," etc.What it means: According to the Oxford English Dictionary, the phrase is "a polite expression used when acknowledging a gift, service, or compliment."Pros and cons: "Thank you" can sound forced. "Thanks," on the other hand, is pithy and versatile. Just don't use it too much in a back-and-forth, lest you sound like an apologist. (Thanks.)Typically used by: Everyone! (Except for The New York Times' Nick Bilton, apparently.)

1. "Sincerely,"What it means: "With sincerity." "Sincere" is believed to be derived from two Latin words: Sine (without) and cera (wax). According to lore, ancient sculptors often used wax in their stone statues to hide their mistakes. Thus, a sculpture "without wax" was the work of an honest man.Pros and cons: Deliberate. Concise. Formal. Ubiquitous. Basically, it's everything you could want in a proper sign-off. In Etiquette, Post calls it "the best ending to a formal social note" available (p. 294). We tend to agree. Typically used by: People who know what they're doing.